4  9i  6  '  /*  t/f*'' 


U.  S.  DEPARTMENT  OE  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  127,  Part  I. 

L.  O.  HOWARD,  Entomologist  and  Chief  of  Bureau. 


PAPERS  ON  INSECTS  AFFECTING  VEGETABLE 
AND  TRUCK  CROPS. 


THE  SPOTTED  BEET  WEBWOKM. 


BY 


F.  H.  CHITTENDEN,  Sc.  D., 

In  <  'harge  of  Truck  (  rop  and  Stored  Product  Insect  Investigations. 


Issued  May  31,  1913 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1913. 


BUREAU  OF   ENTOMOLOGY. 

L.   O.   Howaku,    Entomologist   and   Chief  of   Bureau. 

C.  L.  Marlatt,  Entomologist  and  Acting  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

W.  F.  Tastet,  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truckcropand  stored  product  insect  investigation*. 

A.  D.  Hopkins,  in  charge  of  forest  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Quaintance,  in  charge  of  deciduous  fruit  insert  investigations. 

E.  F.  Phillips,  in  charge  of  bee  culture. 

D.  M.  Rogers,  in  charge  of  preventing  spread  of  moths,  field  work. 

Rolla  P.  Currie,  in  charge  of  editorial  work. 

Mabel  Colcord.  in  charge  of  library. 

Truck  Crop  and  Stored  Product  Insect  Investigations. 
F.  H.  Chittenden,  in  charge. 

C.  H.  Popenoe.  Wm.  B.  Parker,  M.  M.  High,  H.  ().  Marsh.  John  E.  Graf, 
Fred  A.  Johnston,  D.  E.  Fink.  C.  F.  Stahl,  A.  B.  Duckett,  entomological 
assistants. 

I.  J.  Condit.  R.  S.  Yaile,  collaborators  in  California. 

Henry  N.  Ord,  collaborator  in  Oregon. 

Thos.  H.  Jones,  collaborator  in  Porto  Rico. 

Marion  T.  Van  Horn.  Pauline  M.  Johnson,  Anita  M.  Ballinger.  Cecilia 
Sisco.  preparators. 

ii 


CONTENTS. 


Page. 

Introductory • I 

Descriptive 1 

The  moth 1 

The  egg 2 

The  larva 3 

Distribution 3 

Notes  on  occurrence 4 

Attack  on  beets  and  chard 4 

Injury  to  ornamental  plants 5 

Other  records  and  notes 6 

Associated  insects 7 

The  yellow-necked  flea-beetle  (Disonycha  mellicollis  Say ) 7 

The  spinach  flea-beetle  (Disonycha  xanlhomehena  Dalm. ) 8 

The  Hawaiian  beet  webworm  (Ilymenia  fascial  is  Cram.) 9 

Natural  enemies 9 

Control 10 

Bibliography 11 


ILLUSTRATIONS. 


PLATES. 

Page. 
Plate  I.  Swiss  chard  injured  by  the  spotted  beet  webworm  (Ilymenia  perspec- 

talis) 4 

II.  Sugar  beets  showing  injury  from  combined  attack  of  spotted  beet 

webworm  and  spinach  flea-beetle 4 

III.  Swiss  chard  in  same  row  as  shown  in  Plate  I,  not  attacked  by  the 

spotted  beet  webworm.  but  showing  mild  attack  by  the  spinach 
flea-beet  le 4 

IV.  Fig.  1. — Male  and  female  moths  of  the  spotted  beet  webworm.     Fig. 

2. — Moth  of  the  Hawaiian  beet  webworm  ( IIym<  n  in  fascialis) 8 

TEXT   FIGURES. 

Fn..  1.  The  spotted  beet  webworm  (Ilymenia  perspectalisr.  Moth,  larva  and 

details 2 

2.  The  Hawaiian  beet  webworm  (Ilymenia  fascialis):  Wing  venation,  show- 

ing characters  of  genus;  head  and  antenna 3 

3.  The    spotted    beet    webworm    (Ilymenia    perspectalis):  External   male 

characters 3 

7S051°— 13  HI 


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http://archive.org/details/inse14unit 


V.  S.  P.  A.,  R.  E.  Bui.  127.  Part  I.  T.  C.  &  S.  P.  I.  I.,  May  31,   1013. 

PAPERS  ON  INSECTS  AFFECTING  VEGETABLE  AND 
TRUCK  CHOPS. 


THE   SPOTTED  BEET  WEBWORM. 
{Hymema  perspectalis  Hiitra.) 

Ry  F.  H.  Chittenden,  Sc.  D.. 
///  Charge  of  Truck  Crop  and  Stored  Product  Insect  Investigations. 

INTRODUCTORY. 

The  spotted  beet  webworm  (Hymenia  perspectcMs  Hiibn.)  has  at- 
tracted the  writer's  attention  on  two  occasions  from  its  occurrence  on 
beets  in  the  District  of  Columbia.  It  is  a  singular  fact  that  it  was 
first  observed  in  1905  and  that  its  presence  did  not  again  become  no- 
ticeable until  after  a  lapse  of  seven  years,  or  until  1912,  when  it  became 
a  veritable  pest.  It  may  be  classified  both  as  an  enemy  to  sugar  beet, 
because  of  its  occurrence  on  that  plant  normally,  and  as  an  insect 
injurious  to  ornamental  plants  in  both  the  garden  and  greenhouse. 
The  larva  is  at  first  sight  rather  plain,  but  on  closer  examination  it  is 
seen  to  be  distinctly  and  beautifully  marked.  The  moth  is  also  a 
most  beautiful  creature  and  has  often  been  found  flying  about  the 
District  of  Columbia.  The  food  plants  which  will  be  mentioned  in 
the  present  paper  probably  do  not  by  any  means  exhaust  the  list. 

DESCRIPTIVE. 

THE   MOTH. 

Hymenia  perspectalis  is  a  member  of  the  family  Pyralidse  and  sub- 
family Pyraustina\  according  to  Dr.  Dyar's  classification.  It  has  been 
described  under  various  synonyms  as  follows:  Spoladia  animalis 
(iuen..  S.  exportcilis  Guen..  Zinckenia  primordialis  Zell.,  Desmia 
rhinthonalia  Walw.,  and  Hymema  pharsiusalis  Walk. 

The  genus  (under  the  name  Zinckenia)  is  characterized  by  Sir 
GeoBge  Hampson  as  follows: 

Palpi  upturned,  the  2nd  joint  broadly  scaled  in  front  and  not  reaching  vertex 
of  head,  the  3rd  well  developed  and  acuminate;  maxillary  palpi  long  and  fili- 
form ;  frons  rounded;  antennae  of  male  nearly  simple,  the  base  of  shaft  excised, 

1 


2       INSECTS  AFFECTING  VEGETABLE  AND  TRUCK  CROPS. 

and  a  tuft  of  hair  [rising]  from  basal  joint  :  tibia?  with  the  spurs  long  and  Dearly 
equal.  Fore  wing  with  veins  3,  4.  5  from  angle  of  cell;  7  well  separated  from 
8,  0,  to  which  10  is  approximated.  Hind  wing  with  vein  3  from  angle  of  cell; 
4.  .J  approximated  for  a  short  distance:  0.  7  from  upper  angle,  7  anastomosing 
with  8. 

THE    EGG. 

The  egg  was  not  seen  by  the  writer  owing  to  the  lateness  of  the 
season  when  continuous  work  was  begun.  We  therefore  have  t<» 
depend  npon  the  description  furnished  by  Mr.  Davis.  He  writes, 
in  substance,  that  the  female  deposits  her  eggs  flat  and  singlv  on  the 
stem  of  the  plant  near  the  base.  The  egg  is  oval.  0..'»7  nun.  by  0.82 
mm.,  and  being  transparent  pale  green  is  quite  conspicuous  on  the 
plant.  Its  surface  is  slightly  convex  and  covered  with  microscopical, 
irregular  polygonal  areas  appearing  as  a  netlike  sculpture  on  the 
surface. 

Walker's  description  of  the  species  under  the  name  phrasixsalis 
follows : 

Female.     Brown,    rather  slender,   whitish  beneath.     Palpi   vertical,    slightly 

curved,  rising  higher  than  the 
head:  second  joint  slightly 
fringed;  third  lanceolate, 
about  half  the  length  of  the 
second.  Pectus  pure  white  in 
front.  Abdomen  extending  a 
little  beyond  the  hind  wings; 
hind  borders  of  the  segments 
white.  Fore  legs  with  brown 
bands.  Wings  moderately 
broad,  with  a  cupreous  tinge; 
markings  white;  fringe  here 
and  there  white.  Fore  wings 
with  the  interior  line  slender, 
nearly  straight;  exterior  line 
much  interrupted,  broad  and 
regular  in  front:  reniform 
mark  represented  by  a  trans- 
verse subquadrate  spot.  Hind 
wings   with    the   exterior    line 

broad,    complete,   attenuated   hindward.     Length   of   the   body   4    lines;    of   the 

wings  ft  lines. 


Fig.  1. — The  spotted  beet  webworm  [Hffmenia  pcr- 
spcctalisi:  a,  Moth;  b,  larva,  lateral  view:  r, 
larva,  dorsal  view,  showing  characteristic  mark 
ings  on  head  and  joints  :  </,  abdominal  joint  :  c, 
anal  joint,  a-c,  Enlarged  ;  tf,  e,  more  enlarged. 
(Original.) 


Less  technically,  this  moth  may  be  described,  in  comparison  with 
the  related  Hymenia  fascialis  Cram..1  as  of  very  similar  form  and 
having  a  similar  pattern.  The  color  is  paler  brown,  inclining  to 
cinnamon.  The  white  fasciae  or  bands  are  much  less  conspicuous, 
especially  the  second  band  on  the  fore  wing  two-thirds  from  the 
apex.  The  fascia  on  the  hind  wings  is  of  different  shape,  not  more 
than  half  as  wide  as  in  the  other  species,  and  more  irregular.     The 


1  See  Bui.  100,  I't.  I,  Bur.  Ent..  I'.  S.  Dept  Agr.,  November  0,  1912. 


[UK    SPOTTED    BEET    WEBWORM. 


pattern  is  about  as  illustrated  in  figure  1,  a.  The  average  wing  ex- 
panse is  20  nun.,  while  the  body  is  8  mm.  long.  The  venation  is  as 
shown  in  figure  2,  and  the  external  male  characters  are  illustrated 
in  figure  3. 

THE  LARVA. 

The  larva  of  this  species  is.  when  nearly  mature,  subcylindrical 
and  somewhat  depressed.  When  contracted  it  is  about  ten  times  as 
long  as  it  is  wide,  ami  when  extended  still  longer.  The  general 
color  is  green,  brighter  in  the  younger 
individuals  and  paler  just  before 
transformation.  The  head  is  prettily 
marked  with  purplish  dots,  leaving  a 
white,  longitudinal  center  through 
each  half.  The  head  is  well  divided, 
the  two  lobes  meeting  somewhat  nar- 
rowly. The  thoracic  plate  is  of  about 
the  same  width  as  the  head,  having  a 
black  border  with  conspicuous  tuber- 
cle- clothed  with  rather  long  hairs. 
Of  these  tubercles  there  are  two  con- 
spicuous pairs  on  the  first  thoracic  segment,  with  two  others  on  each 
-ide.  The  second  thoracic  segment  is  very  similarly  marked.  The 
abdominal  segments  are  marked  with  four  tubercles  on  the  dorsum 
and  larger  ones  each  side.  The  arrangement  of  the  spots  on  the 
anal  segment  is  well  shown  in  figure  1  at  e.  The  location  of  all 
these  tubercles  is  well  illustrated  in  figure  1, 
the  arrangement  from  above  being  shown  at  c 
and  the  lateral  arrangement  at  b.  The  length 
^>^r3  °*'   tn*s   larva    wa€B   extended    is   about    20   mm. 

'  ■  /u\  l%  Itoa\  When  at  rest,  or  retracted,  it  is  considerabty 
less.  The  width  at  the  widest  portion  is  about 
•2..")  mm. 

The  pupa,  unfortunately,  was  not  preserved. 


Fin.  2. — Venation  of  Hymenia  fas- 
ciulifi,  showing  characters  of  t  lie 
mnus:   head  and  antenna,   lateral 

view,  at  right.      (After   Hampson.) 


PIG.  3. — E  x  t  e  r  n  a  1 
male  characters  of 
moth  of  II  linn  i' in 
pi  rspectalis.  Great- 
ly enlarged.  (Orig- 
inal, i 


DISTRIBUTION. 


tialian   regions. 


The  distribution  accorded  this  species  by  Hamp- 
son is  '•  Xearctic.  Xeotropical.-Ethiopian.  and  Aus- 
Nothing  is  known  of  the  origin  of  the  species, 
and  it  is  uncertain  whether  it  comes  from  the  Old  or  the  Xew 
World,  but  it  is  obviously  exotic  and  introduced  into  the  United 
States.  As  the  known  species  are  from  Africa,  this  may  indicate 
the  original  habitat.  The  species  is  not  known  in  Europe,  but  it 
will  probably  in  time  become  cosmopolitan. 


4        INSECTS  AFFECTING  VEGETABLE  AND  TRUCK  CROPS. 

The  record  of  injurious  occurrences  includes  only  Brooklyn.  X.  Y.. 
and  Washington,  D.  C.  Undoubtedly  the  .species  occurs  in  trouble? 
some  numbers  in  many  localities,  but  no  records  are  available. 

Through  the  kindness  of  Dr.  H.  G.  Dyar  and  from  other  sources 
I  am  enabled  to  furnish  the  folio-wing  distribution: 


Washington,  D.  C.  October  1,  is?!). 

Kansas.  September,  1*72. 

Ohio. 

Georgia,  A] nil.  1879. 

Hurricane  Mills.  Tenn.  (G.  G.  Ainslie). 

Brownsville,  Tex.  (McMillan). 

Tryon,    N.    C,    July   3,    1904    |  W.    F. 

Fiske  i . 
Dallas.  Tex.   (Boll). 
Texas  ( Bel f rage). 
Miami.  Fla.  (Schaus). 
Peruauibuco,  Brazil  (Koebele). 
Oaxaca.  Mexico. 


Grenada,  British  West  Indies. 

St.  Lucia,  British  West   Indies 

Guatemala   (Cockerell). 

Costa  Rica  i  Schaus). 

Panama  (Busck  i. 

Venezuela. 

French  Guiana. 

Peru. 

Bio  de  Janeiro.  Brazil. 

Newark,  N.  J. 

Cuba. 

Sarawak,  Borneo. 

Central  America. 


NOTES   ON   OCCURRENCE. 
ATTACK    OX    BEETS    AND    CHARD. 

October  1,  1005.  the  writer  first  observed  this  species  in  a  small 
colony  on  sugar  beets  growing  in  the  insectary  garden  connected 
with  the  Bureau  of  Entomology.  The  insect  was  studied  at  that  time 
with  sufficient  care  to  enable  a  drawing  of  the  larva  to  be  made,  which 
is  presented  herewith.  The  moth,  however,  was  not  reared  because  of 
an  accident  which  occurred  to  the  rearing  jar  in  the  writer's  absence. 

September  30.  1012.  after  a  lapse  of  seven  years,  this  same  species 
was  again  detected  by  the  writer  and  readily  recognized  from  the 
drawing  previously  made.  It  was  first  noticed  and  caused  consider- 
able injury  on  Swiss  chard  growing  in  the  grounds  of  the  Bureau  of 
Entomology.  The  infestation  covered  one-half  of  a  row  of  chard, 
where  the  damage  was  practically  complete.  Injury,  however,  was 
complicated  by  another  insect  with  which  it  was  associated,  the  spin- 
ach or  beet  flea-beetle  (Disonycha  xanthomeloena  Dalm.).  which  had 
been  injurious  to  the  same  plants  in  an  earlier  and  a  later  generation 
and  was  still  at  work  throughout  the  time  that  the  lepidopterous 
larva  was  observed,  and  even  later.  The  work  of  both  species  is  illus- 
trated in  Plates  I  and  II.  while  Plate  III  shows,  for  comparison,  a 
chard  plant  which  has  been  slightly  infested  but  not  injured.  The 
huge  holes  were  made  chiefly  by  the  beetles  earlier  in  the  season,  and 
the  blacker  portions  show  where  the  larva1  or  caterpillars  did  their 
greatest  damage. 

From  the  outset  of  attack  it  was  noticed  that  larva-  were  rarely 
seen  during  the  daytime  and  evidently  were  nocturnal  or  practically 


Bui.   127,  Part  I,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agnc  iltun 


Plate  I. 


B.I.  127,  Part  I,  Bureau  of  Entomology,  U.  S.  Dept.  of  Agriculture. 


Plate  II 


27,  Part  I,  Bureau  of  Entomology,  U.  S.  Dept.  of  Ag-iculture. 


Plate  111. 


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THE   SPOTTED   BEET   WEBWORM.  5 

so.  and  that  they  concealed  themselves  about  the  bases  of  the  plants 
near  the  roots  and  under  portions  of  leaves  or  petioles  which  rested 
on  the  "•round.  This  was  especially  noticeable  at  the  time  when  the 
larva    were  attaining  their  full  growth. 

Subsequently,  October  '■).  the  writer,  with  Mr.  A.  B.  Ducket  t,  found 
larva1  of  this  species  at  work  on  table  and  sugar  beets.  On  the  sugar 
beet-  similar  injury  to  that  on  Swiss  chard  had  been  done,  but  for 
some  reason  the  larvae  were  scarce.  The  work  was  quite  apparent. 
however.  On  the  table  beets  the  larva1  looked  considerably  darker, 
due  to  the  darker  food  plant  on  which  they  fed.  They  were  ob- 
served at  this  time  in  all  stages  of  growth  from  the  first  stages  of  the 
larva  to  the  last  stage.  The  location  of  the  chard  and  table  and  sugar 
beets  had  much  to  do  with  the  growth  of  the  larva,  the  sun  playing 
an.  important  part. 

On  a  single  leaf  of  sugar  beet  taken  October  4  the  larva  remained 
in  the  same  position  for  about  -2-1  hours.  The  leaf  was  small,  and 
after  this  period,  after  capture,  only  slight  growth  of  the  larva  could 
he  observed,  especially  in  the  case  of  the  younger  stages. 

These  latter  were  probably  in  the  second  stage.  They  were  very 
nearly  white,  showing  very  feeble  markings.  They  measure  about 
;?..")  mm.  in  length.  In  what  appears  to  be  the  third  stage  the  larva 
assume  decided  markings,  but  are  not  nearly  so  dark  as  in  the  next 
stage.  They  are  decidedly  green  in  color,  and  measure  about  10  mm. 
in  length. 

In  the  last  stage  the  larvae,  just  before  pupating,  turn  pale  and 
somewhat  yellowish. 

The  cocoon  is  formed  in  different  ways — on  the  plant  and  on  the 
ground — and  is  covered  with  more  or  less  webbing,  and  sometimes 
with  an  abundance  of  black  excrement  which  naturallv  soon  grows 
dry. 

INJURY  TO  ORNAMENTAL  PLANTS. 

On  October  (>.  1012.  the  writer  observed  at  Iowa  Circle.  Washing- 
ton. D.  C..  severe  injury  to  foliage  plants  of  the  order  Amaranthacea?. 
The  most  seriously  injured  area  was  a  large  circle  in  one  of  the  beds 
at  the  west  end  of  the  park.  The  plants  were  practical^  ruined, 
merely  hanging  together  in  shreds.  Opportunity  did  not  offer  to  ob- 
tain the  larva  because  of  the  crowd  of  pedestrians  and  others  seated 
in  the  immediate  vicinity.  On  another  plat  where  the  plants  did  not 
receive  nearly  so  full  sunlight  the  larva  were  found  in  more  abun- 
dance, but  only  half  as  much  injury  had  been  accomplished.  It 
is  plain  that  the  first  lot  had  mostly  matured  and  the  second  lot 
were  near  maturity.  The  plant  in  question,  on  which  the  insects  were 
most  abundant,  was  Telanthera  versicolor,  or  the  Alternanthera  of 
florists. 


b  INSECTS  AFFECTING    VEGETABLE   AND   TRUCK   CROPS. 

There  were  also  beds  of  the  Achyranthes  acuminata  of  florists, 
known  botanically  as  Iresine  Undent,  which  were  slightly  injured  by 

this  pest.  It  was  noticed  that  the  larva?,  as  in  the  case  of  attack  to 
other  low-growing  plants,  rest  chiefly  during  the  daytime  on  the  lower 
leaves  and  near  the  roots. 

( )ctober  7  the  writer  observed  much  injury  to  several  plats  of  Alter- 
nanthera  on  the  grounds  of  the  Department  of  Agriculture,  but  lar\  Be 
were  difficult  to  obtain  until  the  much  injured  lower  leaves  were 
noticed;  then  no  trouble  was  experienced,  Mr.  Duckett  easily  taking 
about  a  dozen.  In  this  case,  as  in  others,  with  the  exception  of  that 
at  Iowa  Circle,  colonies  of  the  spinach  flea-beetle  {JHsonycha  xantho- 
melama.  Dalm.)  were  present  and  had  been  responsible  for  the  early 
injury.  AVhen  first  collected  the  two  species  were  in  the  proportion  of 
five  of  the  flea-beetle  to  two  of  the  webworm,  but  later  the  lepidop- 
terous  larvae  were  found  to  be  doing  the  greatest  damage,  A  few 
young  larvae  were  observed  at  this  time. 

Cut  leaves  of  beets  and  refuse  stems  were  placed  near  the  affected 
Swiss  chard  as  decoys,  with  the  result  that  many  larvae  were  found, 
some  within  the  stems  and  some  of  them  on  the  side  nearest  the 
ground.  Many  were  also  found  on  and  under  leaves1  which  had 
withered. 

Larva?  which  transformed  to  pupa1  October  1  emerged  as  moths 
October  25,  or  in  21  days.  Larva?  which  transformed  to  pupae  Octo- 
ber 12  emerged  on  October  30,  or  in  18'  days.  One  which  pupated 
October  1G  emerged  October  31.  or  in  15  days,  showing  the  length  of 
the  last  generation  of  the  season  to  vary  between  15  and  21  days,  ac- 
cording to  temperature.  None  of  the  moths  which  were  kept  for  the 
purpose  deposited  eggs,  nor  did  any  remain  over  as  larva-,  as  in  the 
case  of  many  related  species  in  hibernation.  Hence  it  is  doubtful  if 
this  species  really  hibernates  in  the  District  of  Columbia,  and  it  may 
be  that  the  region  is  reached  by  moths  which  fly  from  more  southern 
places  in  warm  days  in  spring  or  early  summer.  At  any  rate  injury 
has  never  been  noticed  until  the  autumn.  One  moth  was  captured  by 
the  writer  as  late  as  December  10  in  the  insectary.  It  might  have 
emerged  from  the  plants  there  or  obtained  access  to  the  building  from 
the  outside. 

OTHER   RECORDS  AND    NOTES. 

The  foregoing  records  have  been  made  from  the  writer's  personal 
observations.  In  looking  over  the  notes  of  the  Bureau  of  Ento- 
mology a  much  earlier  record  was  found,  dated  April  1,  1896,  when 
Mr.  Theodore  Pergande  noticed  large  numbers  of  the  moth  flitting 
about  in  the  propagating  house  of  the  Department  of  Agriculture 

1  This  habit  of  concealment  on  the  dried  leaves  is  a  very  common  one  among  both  beeUes 
and  caterpillars.  Disonycha  i-ant homeland  was  observed  in  similar  locations,  even  on 
dried  leaves  growing  high  on  the  plants. 


THE   SPOTTED   BEET    WEBWOBM.  7 

and  was  told  by  the  gardener  that  this  moth  evidently  belonged  to  a 
small  larva  which  w;is  doing  great  damage  to  the  leaves  of  several 
varieties  of  Alternanthera  grown  in  boxes  and  pots  in  the  green- 
house. It  was  also  observed  that  the  larva'  worked  mainly  at  night 
and  that  they  concealed  themselves  during  the  daytime  between  the 
roots  (if  these  plants  at  the  bottom  of  the  pot. 

November  27,  1909,  Dr.  II.  T.  Fernald  sent  specimens  of  this  spe~ 
cies  for  identification  that  had  been  received  from  Cuba. 

November  15,  1910,  Mr.  D.  K.  McMillan,  while  working  under  the 
writer's  direction  at  Brownsville.  Tex.,  collected  the  larvae  of  this 
species  on  Amaranthus  and  beets  in  that  vicinity.  The  larva1  were 
attacking  the  leaves  and  flowers  of  both  plants  and  webbing  the 
leaves  and  stems.  Moths  were  very  numerous  on  December  G  of  the 
same  year,  a  few  larva1  still  being  found  on  the  food  plants  men- 
tioned.    Parasites  were  reared  from  larva1  taken  November  15. 

April  11.  1912,  Prof.  Glenn  W.  Herrick,  of  Cornell  University, 
Ithaca.  N.  Y..  sent  specimens  of  the  moth  with  report  that  they  were 
reared  from  larva*  found  very  abundantly  in  a  greenhouse  in  Brook- 
lyn. N.  Y..  and  that  they  were  especially  bad  on  Alternanthera. 

Mr.  John  June  Davis  has  forestalled  the  writer  in  publishing  an 
article  on  this  same  species,  which  he  terms  the  Alternanthera  worm. 
He  records  that  in  1910  this  species  was  found  eating  the  foliage  of 
the  variegated  border  plant  Alternanthera.  and  states,  what  the  writer 
has  also  noted,  that  if  the  larva*  are  numerous  enough  to  attract  at- 
tention they  usually  defoliate  the  plant  repeatedly  as  new  shoots 
and  leaves  put  forth,  thus  ruining  it  for  ornamental  purposes  and 
sometimes  killing  it.  The  article  includes  descriptive  matter,  notes 
on  habits,  and  suggestions  as  to  remedial  measures,  among  which 
arsenicals,  hand  picking,  and  light  traps  are  especially  mentioned. 

ASSOCIATED   INSECTS. 
THE   YELLOW-XECKEI)   FLEA-IVEETLE.1 

(Diaonycka   mellieollis  Say.) 

October  8.  1912,  the  writer  observed,  in  a  badly  infested  plat  not 
previously  examined  in  Iowa  Circle.  Washington  City,  about  20  indi- 
viduals of  the  yellow-necked  flea-beetle  {Disonycha  meUicollis  Say) 
congregated  in  a  space  of  less  than  a  square  foot.  They  were  in  a 
warm  place,  the  sunlight  was  strong,  and  hence  they  could  all  have 
escaped,  though  they  could  have  been  captured  that  evening.  The 
writer  captured  enough  specimens  to  be  sure  of  the  species,  although 
this  insect  can  be  readily  separated  from  xanthamelcena  in  life  some- 

iSee  also  Bui.  82,  Pt.  II.  Bur.  Ent.,  I".  S.  Dept.  Agr.,  pp.  2V»-:".J,  1909. 


8        INSECTS  AFFECTING  VEGETABLE  AND  TBUCK  CROPS. 

what  better  than  in  dried  specimens.  It  is  singular  that  this  park 
should  have  been  so  badly  infested  by  this  species,  while  only  one 
individual  could  be  found  in  a  long  search  on  the  grounds  of  the 
Department  of  Agriculture.  The  difference  in  distance  is  not  more 
than  1J  miles. 

THE   SPINACH   FLEA-BEETLE. 

(Disonyclia   xanthomelcena   D;ilm.) 

During  the  year  1912  beets  as  well  as  spinach  grew  very  rapidly 
in  the  District  of  Columbia  during  rainy  days,  succeeded  by  wanner 
ones,  but  owing  to  press  of  other  work  the  writer  was  unable  to  give 
them  and  their  insect  enemies  as  much  personal  attention  as  thev 
deserved,  and  another  reason  was  that  the  species  involved,  Disonycha 
xanthomelcena  Dalm.,  has  already  been  written  up  with  considerable 
care. 

Nevertheless  there  is  always  something  new  to  learn,  as  there  will 
be  of  all  species,  as  long  as  we  continue  to  observe  them  under  dif- 
ferent environments  and  atmospheric  conditions.  The  table  beets 
grew  so  rapidly  that  in  spite  of  the  larva1  and  adults  of  the  spinach 
flea -beetle,  which  "  peppered  them  full  of  holes,"  they  made  consid- 
erable progress. 

The  spinach  began  to  die  rapidly  about  the  beginning  of  the  third 
week  of  June,  and  in  four  days  nearly  every  plant  appeared  as  if  dying. 
In  addition  to  the  spinach  flea-beetle,  the  spinach  aphis  (RhopaZosi- 
phum  dianthi  or  Myzus  persicce  auct.)  was  also  present,  but,  as 
affirmed  by  Dr.  Erwin  F.  Smith,  who,  with  the  writer,  examined 
the  plants  June  25,  there  was  no  evidence  of  disease  or  of  malnutri- 
tion. If  the  plat  of  spinach  had  been  a  field,  the  plants  would  un- 
doubtedly have  perished,  owing  to  the  combined  attack  of  the  flea- 
beetles  and  the  aphides,  and  this  in  spite  of  the  fact  that  the  aphides 
were  being  rapidly  destroyed  by  ladybirds. 

To  determine  the  extent  or  degree  of  injury,  comparison  was  made 
of  a  beet  root  taken  from  our  experimental  plat,  which  had  been  very 
little  affected  by  this  flea-beetle,  with  another  lot  which  had  been 
badly  affected,  with  the  result  that  it  required  nine  of  the  affected 
roots  to  equal  the  weight  of  one  that  was  practically  unaffected. 
The  small  roots  were  picked  out  at  random  by  the  writer  from  the 
place  most  badly  affected,  which  was  at  the  sunny  end  of  the  plat. 

It  should  be  mentioned  in  this  connection  that  plants  growing 
where  they  were  shaded  by  hedge  plants  were  comparatively  little 
affected  by  insects.  This  same  observation  has  been  made  in  connec- 
tion with  the  imported  cabbage  caterpillar  (Pontia  rapce  L.),  which  is 
not  disturbed  by  wasps  when  feeding  in  shady  places. 


Bui.  127,  Part  I,  Bureau  of  Entomology,  U.  S   Dcpt.  of  Agriculture. 


Plate  IV. 


Fig.  1.— Moths  of  the  Spotted  Beet  Webworm  (Hymenia 
perspectalis1,  male  above  and  female  below.  much 
Enlarged.    (Original.) 


Fig.  2.— Moth  of  the  Hawaiian  Beet  Webworm  (Hymenia 
fascialis).    Much  Enlarged.    (After  Marsh.) 


THE    SPOTTED   BEET    WEBWORM.  9 

Evidently  this  and  other  species  of  flea-beetles,  or  at  least  many  of 
them,  are  in  the  habit  of  feeding  to  some  extent  in  sunshine  as  well 
as  in  shade. 

In  regard  to  remedies  for  the  spinach  flea-l>eetle.  while  conducting 
some  experiments  in  July,  1912.  F.  H.  O'Neill,  student  assistant. 
spraying  tor  cabbage  butterflies  and  honey  bees.1  to  see  if  sweetened 
and  poisoned  substances  would  kill  any  of  them,  observed  that  a 
mixture  of  arsenate  of  lead  used  at  the  rate  of  C,  12,  and  25  pounds, 
and  similar  amounts  of  molasses,  to  100  gallons  of  water,  did  not 
destroy  the  butterflies  or  bees,  but  about  GO  dead  individuals  of  this 
flea -beetle  were  counted  beneath  the  radishes  July  1G.  The  flea- 
beetles  were  not  in  particular  evidence  during  these  days;  but  they 
had  "  peppered  "  the  beets  with  the  usual  small  holes  and  must, 
therefore,  have  been  abundant  about  the  roots  of  the  plants  and  come 
up  to  feed  on  the  leaves,  to  their  very  swift  undoing.  It  was  not 
expected  that  the  poison  would  kill  either  the  butterflies  or  the  honey 
bees  which  were  present,  and  these  were  practically  all  unharmed. 

THE   HAWAIIAN    BEET   WEBWORM. 

(Hymcnia  fascialis  Cram.) 

In  a  single  instance  the  Hawaiian  beet  webworm  (Hymenia  fascia- 
lis Cram.)  was  reared  from  Swiss  chard  with  the  spotted  webAvorm 
at  Washington.  D.  C  Moths  issued  on  October  7.  The  chard  is  a 
new  food  plant.  The  species  is  recorded  by  Marsh  as  attacking  table 
and  sugar  beets,  stock  beets  or  mangel-wurzels,  and  several  species  of 
Amaranthus,  Euxolus,  purslane  (Portidaca  oleracea),  cucumbers,  and 
chenopodiaceous  weeds.  The  moths  of  the  two  species  are  shown,  for 
comparison,  in  Plate  IV. 

NATURAL   ENEMIES. 

On  several  occasions  during  October  the  last  two  stages  of  the 
nymph  of  the  spined  soldier-bug  {Podisus  maeuliventris  Say)  were 
observed  attacking  the  larva?  of  the  spotted  beet  webworm.  This 
was  the  only  predaceous  insect  observed,  although  there  are  probably 
several  others. 

The  same  is  true  of  the  parasitic  enemies,  a  single  one  being  noticed, 
a  small  braconid,  Hemiteles  sp.  (Chttn.  No.  2194°).  This  latter 
was  reared  October  7. 

The  very  closely-related  Hymenia  fascialis  has  several  parasites, 
and  the  probabilities  are  that  if  the  present  species  were  studied  more 
carefully  in  other  regions  a  number  of  other  natural  enemies  would 

1  These   experiments   were   made  at  the   request   of   correspondents. 


10      INSECTS  AFFECTINc;  VEGETABLE  AND  TRUCK  CROPS. 

be  discovered.  Undoubtedly  also  wasps  of  the  genus  Polistes,  be- 
sidea  Limneriwm  kawaMense  Cram..  Chelowus  blackburni  Cram.,  and 
Cremastus  hymema  Vier.,  enemies  of  II.  fascidlis  in  Hawaii,  will 
attack  this  species  in  its  larval  condition. 

CONTROL. 

It  is  obvious  from  the  notes  on  the  occurrence  of  this  insect  that 
injury  was  discovered  too  late  for  the  application  of  insecticides.  In 
practically  every  case  the  larvae  were  in  the  last  stage,  the  few  younger 
larva'  merely  indicating  the  exception  to  the  rule.  Such  being  the 
case  it  was  not  possible  to  test  any  remedies  whatever.  It  is  inter- 
esting to  relate,  however,  in  the  case  of  Swiss  chard,  that  many  of  the 
plants,  being  able  to  withstand  a  considerable  degree  of  cold,  re- 
covered and  put  forth  new  leaves,  practically  a  second  crop  of  leaves 
developing,  and  that  the  moths  hatched  from  all  larvae  and  did  not 
deposit  eggs,  at  least  not  in  confinement.  What  they  would  do  under 
natural  conditions  is  not  quite  certain  for  this  latitude. 

In  the  case  of  the  related  Hawaiian  beet  webworm,  Mr.  H.  O.  Marsh 
has  demonstrated  that  Paris  green  applied  at  the  rate  of  2  pounds 
in  100  gallons  of  water  did  not  burn  beet  foliage,  and  the  same  would 
be  true  of  chard  and  the  ornamental  plants  which  this  species  attacks. 
Whale-oil  soap  at  the  rate  of  8  pounds  to  100  gallons  of  water  is 
added,  and  serves  as  an  effective  adhesive  agent  or  "  sticker."  thus 
enabling  a  more  even  distribution  of  the  poison  over  the  leaf  surfaces. 

In  addition  to  Paris  green.  Mr.  Marsh  demonstrated  that  nicotine 
sulphate,  used  at  the  rate  of  1  fluid  ounce  to  4  ounces  of  whale-oil 
soap  and  I  gallons  of  water,  sprayed  upon  cabbage,  resulted  in  the 
destruction  of  other  small  and  larger  larvae.  He  expresses  the  belief 
also,  reasoning  from  analogy,  that  this  formula,  although  not  actually 
tested  on  Hymenia  larvae,  woidd  probably  prove  entirely  effective. 

Arsenate  of  lead  and  arsenite  of  zinc  should  both  be  tested  for  this 
insect  should  it  occur  in  numbers  and  an  opportunity  be  afforded  for 
an  early  application  of  these  j^oisons  as  sprays.  The  most  important 
item  in  the  control  of  this  insect  is  the  detection  of  injury  early  in  the 
season,  before  actual  damage  is  accomplished.  Among  other  remedies 
fall  plowing  should  be  practiced.  It  is  unwise  to  grow  susceptible 
plants  in  the  same  locality  in  which  this  insect  has  been  abundant 
the  previous  season. 

There  is  no  proof  as  yet  that  as  far  north  as  the  District  of  Colum- 
bia this  species  will  in  the  near  future  renew  attack  or  Income  as  bad 
a  pest  as  in  1912.  The  possibility  exists,  however,  and  a  close  look- 
out will  be  kept  for  its  reappearance. 


THE    SPOTTED   BEET    WEBWOHM.  11 

BIBLIOGRAPHY. 

1.  Hubnkr.  Jacob.— Sekmett.  Eur.,  Pyr.,  fig.  101,  179<>.     (Not  seen.) 

2.  Zki.i.ku.  P.  C. — Lep.  Microptera  In  Caffrorum<K.  Vet.  Akad.    Handl.,  stock- 

holm,  1S54,  pp.  55-57,  1S52. 

Characterization  of  genus  Zinckenia  and  description  of  primordiaUa  n.  sp. 

3.  Guenee.  M.  A.— Hist.  Nat  inseetes.  Deltoides  et  Pyralites,  Paris,  p.  22<;,  is.vt. 

Described   as   Spolodea    nerspectalis    from    South   America   and    North   America. 
Occurrence  on  Liliitm  canadenae.    Larva  briefly  described. 

4.  Guenee,  M.  A. — Idem. 

Described  from  l'emambuco,  Brazil,  as  Spolodea  animaUa  n.   sp.     Description  as 
Spolodea  exportaUs  a.  sp..  from  New   Holland   (Australia  I. 

5.  Walker.  Francis.— Cat  Brit.  Lep.  Het.,  vol.  19,  p.  932.  1859. 

Description  as  Desmia  rhinanthalis  n.  sp.,  from  Sarawak.  Borneo. 
0.  Walker.  Francis.— Cat.  Brit.  Lep.  Het.,  vol.  19,  p.  944.  1859. 

Description  as  innncnin  phrasiusalis  n.  sp.,  from  Uio  de  Janeiro,  Brazil. 

7.  Hampson,  Sir  G.  F—  Proc.  Zool.  Soc.  Lond.,  p.  623,  fig.  21  (fascialis),  1898. 

Description  of  genus;  synonymy  and  references  to  species. 

8.  Davis.   John   June.— In  27th   Kept.   State  Ent.   111.,   pp.  103-106,  figs.   16-21, 

1912. 
General   account,   with   notes   on   habits   and   remedies. 


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